Cluster parsing for signaling within multiple user, multiple access, and/or mimo wireless communications

ABSTRACT

Cluster parsing for signaling within multi-user wireless communication systems. Cluster assignment allows for complete flexibility across a variety of operational parameters in accordance with communications provided from a transmitting wireless communication device to a number of receiving wireless communication devices. For example, an access point (AP) may communicate to a number of wireless stations (STAs) in accordance with multi-user multiple input multiple output (MU-MIMO), orthogonal frequency division multiple access (OFDMA), and/or MU-MIMO/OFDMA. The selectivity may involve employing different antenna for communicating with each of the respective, receiving wireless communication devices. Also, the formation of a cluster employed in such communications may involve using as few as one channel within one band, different channels within a single band, different channels within different bands, or other combinations. Signaling corresponding to different clusters may be transmitted using different antenna or different groups of antennae.

CROSS REFERENCE TO RELATED PATENTS/PATENT APPLICATIONS ProvisionalPriority Claims

The present U.S. Utility Patent Application claims priority pursuant to35 U.S.C. §119(e) to the following U.S. Provisional Patent Applicationswhich are hereby incorporated herein by reference in their entirety andmade part of the present U.S. Utility Patent Application for allpurposes:

1. U.S. Provisional Application Ser. No. 61/184,420, entitled “OFDMAcluster parsing and acknowledgement to OFDMA/MU-MIMO transmissions inWLAN device,” (Attorney Docket No. BP20710), filed 06-05-2009, pending.

2. U.S. Provisional Application Ser. No. 61/185,153, entitled “OFDMAcluster parsing and acknowledgement to OFDMA/MU-MIMO transmissions inWLAN device,” (Attorney Docket No. BP20710.1), filed 06-08-2009,pending.

Incorporation by Reference

The following U.S. Utility Patent Application is hereby incorporatedherein by reference in its entirety and is made part of the present U.S.Utility Patent Application for all purposes:

1. U.S. Utility patent application Ser. No. ______, entitled“Transmission acknowledgement within multiple user, multiple access,and/or MIMO wireless communications,” (Attorney Docket No. BP20710.1),filed concurrently on ______, pending.

BACKGROUND OF THE INVENTION

1. Technical Field of the Invention

The invention relates generally to wireless communication systems; and,more particularly to clustering of signaling within such wirelesscommunication systems.

2. Description of Related Art

Communication systems are known to support wireless and wire linedcommunications between wireless and/or wire lined communication devices.Such communication systems range from national and/or internationalcellular telephone systems to the Internet to point-to-point in-homewireless networks. Each type of communication system is constructed, andhence operates, in accordance with one or more communication standards.For instance, wireless communication systems may operate in accordancewith one or more standards including, but not limited to, IEEE 802.11x,Bluetooth, advanced mobile phone services (AMPS), digital AMPS, globalsystem for mobile communications (GSM), code division multiple access(CDMA), local multi-point distribution systems (LMDS),multi-channel-multi-point distribution systems (MMDS), and/or variationsthereof.

Depending on the type of wireless communication system, a wirelesscommunication device, such as a cellular telephone, two-way radio,personal digital assistant (PDA), personal computer (PC), laptopcomputer, home entertainment equipment, et cetera communicates directlyor indirectly with other wireless communication devices. For directcommunications (also known as point-to-point communications), theparticipating wireless communication devices tune their receivers andtransmitters to the same channel or channels (e.g., one of the pluralityof radio frequency (RF) carriers of the wireless communication system)and communicate over that channel(s). For indirect wirelesscommunications, each wireless communication device communicates directlywith an associated base station (e.g., for cellular services) and/or anassociated access point (e.g., for an in-home or in-building wirelessnetwork) via an assigned channel. To complete a communication connectionbetween the wireless communication devices, the associated base stationsand/or associated access points communicate with each other directly,via a system controller, via the public switch telephone network, viathe Internet, and/or via some other wide area network.

For each wireless communication device to participate in wirelesscommunications, it includes a built-in radio transceiver (i.e., receiverand transmitter) or is coupled to an associated radio transceiver (e.g.,a station for in-home and/or in-building wireless communicationnetworks, RF modem, etc.). As is known, the receiver is coupled to theantenna and includes a low noise amplifier, one or more intermediatefrequency stages, a filtering stage, and a data recovery stage. The lownoise amplifier receives inbound RF signals via the antenna andamplifies then. The one or more intermediate frequency stages mix theamplified RF signals with one or more local oscillations to convert theamplified RF signal into baseband signals or intermediate frequency (IF)signals. The filtering stage filters the baseband signals or the IFsignals to attenuate unwanted out of band signals to produce filteredsignals. The data recovery stage recovers raw data from the filteredsignals in accordance with the particular wireless communicationstandard.

As is also known, the transmitter includes a data modulation stage, oneor more intermediate frequency stages, and a power amplifier. The datamodulation stage converts raw data into baseband signals in accordancewith a particular wireless communication standard. The one or moreintermediate frequency stages mix the baseband signals with one or morelocal oscillations to produce RF signals. The power amplifier amplifiesthe RF signals prior to transmission via an antenna.

Typically, the transmitter will include one antenna for transmitting theRF signals, which are received by a single antenna, or multiple antennae(alternatively, antennas), of a receiver. When the receiver includes twoor more antennae, the receiver will select one of them to receive theincoming RF signals. In this instance, the wireless communicationbetween the transmitter and receiver is a single-output-single-input(SISO) communication, even if the receiver includes multiple antennaethat are used as diversity antennae (i.e., selecting one of them toreceive the incoming RF signals). For SISO wireless communications, atransceiver includes one transmitter and one receiver. Currently, mostwireless local area networks (WLAN) that are IEEE 802.11, 802.11a,802.11b, or 802.11g employ SISO wireless communications.

Other types of wireless communications includesingle-input-multiple-output (SIMO), multiple-input-single-output(MISO), and multiple-input-multiple-output (MIMO). In a SIMO wirelesscommunication, a single transmitter processes data into radio frequencysignals that are transmitted to a receiver. The receiver includes two ormore antennae and two or more receiver paths. Each of the antennaereceives the RF signals and provides them to a corresponding receiverpath (e.g., LNA, down conversion module, filters, and ADCs). Each of thereceiver paths processes the received RF signals to produce digitalsignals, which are combined and then processed to recapture thetransmitted data.

For a multiple-input-single-output (MISO) wireless communication, thetransmitter includes two or more transmission paths (e.g., digital toanalog converter, filters, up-conversion module, and a power amplifier)that each converts a corresponding portion of baseband signals into RFsignals, which are transmitted via corresponding antennae to a receiver.The receiver includes a single receiver path that receives the multipleRF signals from the transmitter. In this instance, the receiver usesbeam forming to combine the multiple RF signals into one signal forprocessing.

For a multiple-input-multiple-output (MIMO) wireless communication, thetransmitter and receiver each include multiple paths. In such acommunication, the transmitter parallel processes data using a spatialand time encoding function to produce two or more streams of data. Thetransmitter includes multiple transmission paths to convert each streamof data into multiple RF signals. The receiver receives the multiple RFsignals via multiple receiver paths that recapture the streams of datautilizing a spatial and time decoding function. The recaptured streamsof data are combined and subsequently processed to recover the originaldata.

With the various types of wireless communications (e.g., SISO, MISO,SIMO, and MIMO), it would be desirable to use one or more types ofwireless communications to enhance data throughput within a WLAN. Forexample, high data rates can be achieved with MIMO communications incomparison to SISO communications. However, most WLAN include legacywireless communication devices (i.e., devices that are compliant with anolder version of a wireless communication standard). As such, atransmitter capable of MIMO wireless communications should also bebackward compatible with legacy devices to function in a majority ofexisting WLANs.

Therefore, a need exists for a WLAN device that is capable of high datathroughput and is backward compatible with legacy devices.

BRIEF SUMMARY OF THE INVENTION

The present invention is directed to apparatus and methods of operationthat are further described in the following Brief Description of theSeveral Views of the Drawings, the Detailed Description of theInvention, and the claims. Other features and advantages of the presentinvention will become apparent from the following detailed descriptionof the invention made with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 is a diagram illustrating an embodiment of a wirelesscommunication system.

FIG. 2 is a diagram illustrating an embodiment of a wirelesscommunication device.

FIG. 3 is a diagram illustrating an embodiment of a radio frequency (RF)transmitter.

FIG. 4 is a diagram illustrating an embodiment of an RF receiver.

FIG. 5 is a diagram illustrating an embodiment of a method for basebandprocessing of data.

FIG. 6 is a diagram illustrating an embodiment of a method that furtherdefines Step 120 of FIG. 5.

FIGS. 7-9 are diagrams illustrating various embodiments for encoding thescrambled data.

FIGS. 10A and 10B are diagrams illustrating embodiments of a radiotransmitter.

FIGS. 11A and 11B are diagrams illustrating embodiments of a radioreceiver.

FIG. 12 is a diagram illustrating an embodiment of an access point (AP)and multiple wireless local area network (WLAN) devices operatingaccording to one or more various aspects and/or embodiments of theinvention.

FIG. 13A is a diagram illustrating an embodiment of a structure employedby an access point (or WLAN) device supporting orthogonal frequencydivision multiple access (OFDMA) cluster parsing.

FIG. 13B is a diagram illustrating an embodiment of a structure employedby an access point (or WLAN) device supporting multi-user OFDMA(MU-OFDMA).

FIG. 14A is a diagram illustrating an embodiment of a structure used forconveyance of scheduled or slotted start time within an orthogonalfrequency division multiple access (OFDMA)/multi-user multiple inputmultiple output (MU-MIMO) frame as media access control (MAC) frames.

FIG. 14B is a diagram illustrating an embodiment of a structure used forindicating multiple SACK fields in one MAC frame.

FIG. 14C is a diagram illustrating an alternative embodiment of astructure used for indicating multiple SACK fields in one MAC frame.

FIG. 15 is a diagram illustrating an embodiment of a structure used forthe conveyance of start time within an OFDMA/MU-MIMO frame as a PHYHeader extension.

FIGS. 16 and 17 are signal diagrams illustrating embodiments of timeslotted/scheduled acknowledgements showing network allocation vector(NAV) protection for acknowledgements.

FIG. 18 is a signal diagram illustrating an embodiment of time slottedor scheduled acknowledgements that are transmitted in multiple clusters.

FIG. 19 is a signal diagram illustrating an embodiment of time slottedor scheduled acknowledgements that are transmitted in multiple clusterswhen a cluster is not in use.

FIG. 20 is a signal diagram illustrating an embodiment of fixedacknowledgement slotting.

FIGS. 21, 22, 23, 24, 25, 26, 27, 28, and 29 are signal diagramsillustrating embodiments of time slotted or scheduled acknowledgementsequences when one or more STAs share channel (e.g., OFDMA and/orMU-MIMO).

FIGS. 30, 31, and 32 are signal diagrams illustrating variousembodiments of polled ACK operations of transmitting and receiving WLANdevices.

FIGS. 33 and 34 are signal diagrams illustrating various examples ofreverse data aggregations ACK operations of transmitting and receivingWLAN devices.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 is a diagram illustrating an embodiment of a wirelesscommunication system 10 that includes a plurality of base stationsand/or access points 12-16, a plurality of wireless communicationdevices 18-32 and a network hardware component 34. The wirelesscommunication devices 18-32 may be laptop host computers 18 and 26,personal digital assistant hosts 20 and 30, personal computer hosts 24and 32 and/or cellular telephone hosts 22 and 28. The details of anembodiment of such wireless communication devices is described ingreater detail with reference to FIG. 2.

The base stations (BSs) or access points (APs) 12-16 are operablycoupled to the network hardware 34 via local area network connections36, 38 and 40. The network hardware 34, which may be a router, switch,bridge, modem, system controller, et cetera provides a wide area networkconnection 42 for the communication system 10. Each of the base stationsor access points 12-16 has an associated antenna or antenna array tocommunicate with the wireless communication devices in its area.Typically, the wireless communication devices register with a particularbase station or access point 12-14 to receive services from thecommunication system 10. For direct connections (i.e., point-to-pointcommunications), wireless communication devices communicate directly viaan allocated channel.

Typically, base stations are used for cellular telephone systems (e.g.,advanced mobile phone services (AMPS), digital AMPS, global system formobile communications (GSM), code division multiple access (CDMA), localmulti-point distribution systems (LMDS), multi-channel-multi-pointdistribution systems (MMDS), Enhanced Data rates for GSM Evolution(EDGE), General Packet Radio Service (GPRS), high-speed downlink packetaccess (HSDPA), high-speed uplink packet access (HSUPA and/or variationsthereof) and like-type systems, while access points are used for in-homeor in-building wireless networks (e.g., IEEE 802.11, Bluetooth, ZigBee,any other type of radio frequency based network protocol and/orvariations thereof). Regardless of the particular type of communicationsystem, each wireless communication device includes a built-in radioand/or is coupled to a radio. Such wireless communication device mayoperate in accordance with the various aspects of the invention aspresented herein to enhance performance, reduce costs, reduce size,and/or enhance broadband applications.

FIG. 2 is a diagram illustrating an embodiment of a wirelesscommunication device that includes the host device 18-32 and anassociated radio 60. For cellular telephone hosts, the radio 60 is abuilt-in component. For personal digital assistants hosts, laptop hosts,and/or personal computer hosts, the radio 60 may be built-in or anexternally coupled component. For access points or base stations, thecomponents are typically housed in a single structure.

As illustrated, the host device 18-32 includes a processing module 50,memory 52, radio interface 54, input interface 58 and output interface56. The processing module 50 and memory 52 execute the correspondinginstructions that are typically done by the host device. For example,for a cellular telephone host device, the processing module 50 performsthe corresponding communication functions in accordance with aparticular cellular telephone standard.

The radio interface 54 allows data to be received from and sent to theradio 60.

For data received from the radio 60 (e.g., inbound data), the radiointerface 54 provides the data to the processing module 50 for furtherprocessing and/or routing to the output interface 56. The outputinterface 56 provides connectivity to an output display device such as adisplay, monitor, speakers, et cetera such that the received data may bedisplayed. The radio interface 54 also provides data from the processingmodule 50 to the radio 60. The processing module 50 may receive theoutbound data from an input device such as a keyboard, keypad,microphone, et cetera via the input interface 58 or generate the dataitself. For data received via the input interface 58, the processingmodule 50 may perform a corresponding host function on the data and/orroute it to the radio 60 via the radio interface 54.

Radio 60 includes a host interface 62, a baseband processing module 64,memory 66, a plurality of radio frequency (RF) transmitters 68-72, atransmit/receive (T/R) module 74, a plurality of antennae 82-86, aplurality of RF receivers 76-80, and a local oscillation module 100. Thebaseband processing module 64, in combination with operationalinstructions stored in memory 66, execute digital receiver functions anddigital transmitter functions, respectively. The digital receiverfunctions, as will be described in greater detail with reference to FIG.11B, include, but are not limited to, digital intermediate frequency tobaseband conversion, demodulation, constellation demapping, decoding,de-interleaving, fast Fourier transform, cyclic prefix removal, spaceand time decoding, and/or descrambling. The digital transmitterfunctions, as will be described in greater detail with reference tolater Figures, include, but are not limited to, scrambling, encoding,interleaving, constellation mapping, modulation, inverse fast Fouriertransform, cyclic prefix addition, space and time encoding, and/ordigital baseband to IF conversion. The baseband processing modules 64may be implemented using one or more processing devices. Such aprocessing device may be a microprocessor, micro-controller, digitalsignal processor, microcomputer, central processing unit, fieldprogrammable gate array, programmable logic device, state machine, logiccircuitry, analog circuitry, digital circuitry, and/or any device thatmanipulates signals (analog and/or digital) based on operationalinstructions. The memory 66 may be a single memory device or a pluralityof memory devices. Such a memory device may be a read-only memory,random access memory, volatile memory, non-volatile memory, staticmemory, dynamic memory, flash memory, and/or any device that storesdigital information. Note that when the processing module 64 implementsone or more of its functions via a state machine, analog circuitry,digital circuitry, and/or logic circuitry, the memory storing thecorresponding operational instructions is embedded with the circuitrycomprising the state machine, analog circuitry, digital circuitry,and/or logic circuitry.

In operation, the radio 60 receives outbound data 88 from the hostdevice via the host interface 62. The baseband processing module 64receives the outbound data 88 and, based on a mode selection signal 102,produces one or more outbound symbol streams 90. The mode selectionsignal 102 will indicate a particular mode as are illustrated in themode selection tables, which appear at the end of the detaileddiscussion. For example, the mode selection signal 102, with referenceto table 1 may indicate a frequency band of 2.4 GHz or 5 GHz, a channelbandwidth of 20 or 22 MHz (e.g., channels of 20 or 22 MHz width) and amaximum bit rate of 54 megabits-per-second. In other embodiments, thechannel bandwidth may extend up to 1.28 GHz or wider with supportedmaximum bit rates extending to 1 gigabit-per-second or greater. In thisgeneral category, the mode selection signal will further indicate aparticular rate ranging from 1 megabit-per-second to 54megabits-per-second. In addition, the mode selection signal willindicate a particular type of modulation, which includes, but is notlimited to, Barker Code Modulation, BPSK, QPSK, CCK, 16 QAM and/or 64QAM. As is further illustrated in table 1, a code rate is supplied aswell as number of coded bits per subcarrier (NBPSC), coded bits per OFDMsymbol (NCBPS), data bits per OFDM symbol (NDBPS).

The mode selection signal may also indicate a particular channelizationfor the corresponding mode which for the information in table 1 isillustrated in table 2. As shown, table 2 includes a channel number andcorresponding center frequency. The mode select signal may furtherindicate a power spectral density mask value which for table 1 isillustrated in table 3. The mode select signal may alternativelyindicate rates within table 4 that has a 5 GHz frequency band, 20 MHzchannel bandwidth and a maximum bit rate of 54 megabits-per-second. Ifthis is the particular mode select, the channelization is illustrated intable 5. As a further alternative, the mode select signal 102 mayindicate a 2.4 GHz frequency band, 20 MHz channels and a maximum bitrate of 192 megabits-per-second as illustrated in table 6. In table 6, anumber of antennae may be utilized to achieve the higher bit rates. Inthis instance, the mode select would further indicate the number ofantennae to be utilized. Table 7 illustrates the channelization for theset-up of table 6. Table 8 illustrates yet another mode option where thefrequency band is 2.4 GHz, the channel bandwidth is 20 MHz and themaximum bit rate is 192 megabits-per-second. The corresponding table 8includes various bit rates ranging from 12 megabits-per-second to 216megabits-per-second utilizing 2-4 antennae and a spatial time encodingrate as indicated. Table 9 illustrates the channelization for table 8.The mode select signal 102 may further indicate a particular operatingmode as illustrated in table 10, which corresponds to a 5 GHz frequencyband having 40 MHz frequency band having 40 MHz channels and a maximumbit rate of 486 megabits-per-second. As shown in table 10, the bit ratemay range from 13.5 megabits-per-second to 486 megabits-per-secondutilizing 1-4 antennae and a corresponding spatial time code rate. Table10 further illustrates a particular modulation scheme code rate andNBPSC values. Table 11 provides the power spectral density mask fortable 10 and table 12 provides the channelization for table 10.

It is of course noted that other types of channels, having differentbandwidths, may be employed in other embodiments without departing fromthe scope and spirit of the invention. For example, various otherchannels such as those having 80 MHz, 120 MHz, and/or 160 MHz ofbandwidth may alternatively be employed such as in accordance with IEEETask Group ac (TGac VHTL6).

The baseband processing module 64, based on the mode selection signal102 produces the one or more outbound symbol streams 90, as will befurther described with reference to FIGS. 5-9 from the output data 88.For example, if the mode selection signal 102 indicates that a singletransmit antenna is being utilized for the particular mode that has beenselected, the baseband processing module 64 will produce a singleoutbound symbol stream 90. Alternatively, if the mode select signalindicates 2, 3 or 4 antennae, the baseband processing module 64 willproduce 2, 3 or 4 outbound symbol streams 90 corresponding to the numberof antennae from the output data 88.

Depending on the number of outbound streams 90 produced by the basebandmodule 64, a corresponding number of the RF transmitters 68-72 will beenabled to convert the outbound symbol streams 90 into outbound RFsignals 92. The implementation of the RF transmitters 68-72 will befurther described with reference to FIG. 3. The transmit/receive module74 receives the outbound RF signals 92 and provides each outbound RFsignal to a corresponding antenna 82-86.

When the radio 60 is in the receive mode, the transmit/receive module 74receives one or more inbound RF signals via the antennae 82-86. The T/Rmodule 74 provides the inbound RF signals 94 to one or more RF receivers76-80. The RF receiver 76-80, which will be described in greater detailwith reference to FIG. 4, converts the inbound RF signals 94 into acorresponding number of inbound symbol streams 96. The number of inboundsymbol streams 96 will correspond to the particular mode in which thedata was received (recall that the mode may be any one of the modesillustrated in tables 1-12). The baseband processing module 60 receivesthe inbound symbol streams 90 and converts them into inbound data 98,which is provided to the host device 18-32 via the host interface 62.

In one embodiment of radio 60 it includes a transmitter and a receiver.The transmitter may include a MAC module, a PLCP module, and a PMDmodule. The Medium Access Control (MAC) module, which may be implementedwith the processing module 64, is operably coupled to convert a MACService Data Unit (MSDU) into a MAC Protocol Data Unit (MPDU) inaccordance with a WLAN protocol. The Physical Layer ConvergenceProcedure (PLCP) Module, which may be implemented in the processingmodule 64, is operably coupled to convert the MPDU into a PLCP ProtocolData Unit (PPDU) in accordance with the WLAN protocol. The PhysicalMedium Dependent (PMD) module is operably coupled to convert the PPDUinto a plurality of radio frequency (RF) signals in accordance with oneof a plurality of operating modes of the WLAN protocol, wherein theplurality of operating modes includes multiple input and multiple outputcombinations.

An embodiment of the Physical Medium Dependent (PMD) module, which willbe described in greater detail with reference to FIGS. 10A and 10B,includes an error protection module, a demultiplexing module, and aplurality of direction conversion modules. The error protection module,which may be implemented in the processing module 64, is operablycoupled to restructure a PPDU (PLCP (Physical Layer ConvergenceProcedure) Protocol Data Unit) to reduce transmission errors producingerror protected data. The demultiplexing module is operably coupled todivide the error protected data into a plurality of error protected datastreams The plurality of direct conversion modules is operably coupledto convert the plurality of error protected data streams into aplurality of radio frequency (RF) signals.

As one of average skill in the art will appreciate, the wirelesscommunication device of FIG. 2 may be implemented using one or moreintegrated circuits. For example, the host device may be implemented onone integrated circuit, the baseband processing module 64 and memory 66may be implemented on a second integrated circuit, and the remainingcomponents of the radio 60, less the antennae 82-86, may be implementedon a third integrated circuit. As an alternate example, the radio 60 maybe implemented on a single integrated circuit. As yet another example,the processing module 50 of the host device and the baseband processingmodule 64 may be a common processing device implemented on a singleintegrated circuit. Further, the memory 52 and memory 66 may beimplemented on a single integrated circuit and/or on the same integratedcircuit as the common processing modules of processing module 50 and thebaseband processing module 64.

FIG. 3 is a diagram illustrating an embodiment of a radio frequency (RF)transmitter 68-72, or RF front-end, of the WLAN transmitter. The RFtransmitter 68-72 includes a digital filter and up-sampling module 75, adigital-to-analog conversion module 77, an analog filter 79, andup-conversion module 81, a power amplifier 83 and a RF filter 85. Thedigital filter and up-sampling module 75 receives one of the outboundsymbol streams 90 and digitally filters it and then up-samples the rateof the symbol streams to a desired rate to produce the filtered symbolstreams 87. The digital-to-analog conversion module 77 converts thefiltered symbols 87 into analog signals 89. The analog signals mayinclude an in-phase component and a quadrature component.

The analog filter 79 filters the analog signals 89 to produce filteredanalog signals 91. The up-conversion module 81, which may include a pairof mixers and a filter, mixes the filtered analog signals 91 with alocal oscillation 93, which is produced by local oscillation module 100,to produce high frequency signals 95. The frequency of the highfrequency signals 95 corresponds to the frequency of the RF signals 92.

The power amplifier 83 amplifies the high frequency signals 95 toproduce amplified high frequency signals 97. The RF filter 85, which maybe a high frequency band-pass filter, filters the amplified highfrequency signals 97 to produce the desired output RF signals 92.

As one of average skill in the art will appreciate, each of the radiofrequency transmitters 68-72 will include a similar architecture asillustrated in FIG. 3 and further include a shut-down mechanism suchthat when the particular radio frequency transmitter is not required, itis disabled in such a manner that it does not produce interferingsignals and/or noise.

FIG. 4 is a diagram illustrating an embodiment of an RF receiver. Thismay depict any one of the RF receivers 76-80. In this embodiment, eachof the RF receivers 76-80 includes an RF filter 101, a low noiseamplifier (LNA) 103, a programmable gain amplifier (PGA) 105, adown-conversion module 107, an analog filter 109, an analog-to-digitalconversion module 111 and a digital filter and down-sampling module 113.The RF filter 101, which may be a high frequency band-pass filter,receives the inbound RF signals 94 and filters them to produce filteredinbound RF signals. The low noise amplifier 103 amplifies the filteredinbound RF signals 94 based on a gain setting and provides the amplifiedsignals to the programmable gain amplifier 105. The programmable gainamplifier further amplifies the inbound RF signals 94 before providingthem to the down-conversion module 107.

The down-conversion module 107 includes a pair of mixers, a summationmodule, and a filter to mix the inbound RF signals with a localoscillation (LO) that is provided by the local oscillation module toproduce analog baseband signals. The analog filter 109 filters theanalog baseband signals and provides them to the analog-to-digitalconversion module 111 which converts them into a digital signal. Thedigital filter and down-sampling module 113 filters the digital signalsand then adjusts the sampling rate to produce the digital samples(corresponding to the inbound symbol streams 96).

FIG. 5 is a diagram illustrating an embodiment of a method for basebandprocessing of data. This diagram shows a method for converting outbounddata 88 into one or more outbound symbol streams 90 by the basebandprocessing module 64. The process begins at Step 110 where the basebandprocessing module receives the outbound data 88 and a mode selectionsignal 102. The mode selection signal may indicate any one of thevarious modes of operation as indicated in tables 1-12. The process thenproceeds to Step 112 where the baseband processing module scrambles thedata in accordance with a pseudo random sequence to produce scrambleddata. Note that the pseudo random sequence may be generated from afeedback shift register with the generator polynomial of S(x)=x⁷+x⁴+1.

The process then proceeds to Step 114 where the baseband processingmodule selects one of a plurality of encoding modes based on the modeselection signal. The process then proceeds to Step 116 where thebaseband processing module encodes the scrambled data in accordance witha selected encoding mode to produce encoded data. The encoding may bedone utilizing any one or more a variety of coding schemes (e.g.,convolutional coding, Reed-Solomon (RS) coding, turbo coding, turbotrellis coded modulation (TTCM) coding, LDPC (Low Density Parity Check)coding, etc.).

The process then proceeds to Step 118 where the baseband processingmodule determines a number of transmit streams based on the mode selectsignal. For example, the mode select signal will select a particularmode which indicates that 1, 2, 3, 4 or more antennae may be utilizedfor the transmission. Accordingly, the number of transmit streams willcorrespond to the number of antennae indicated by the mode selectsignal. The process then proceeds to Step 120 where the basebandprocessing module converts the encoded data into streams of symbols inaccordance with the number of transmit streams in the mode selectsignal. This step will be described in greater detail with reference toFIG. 6.

FIG. 6 is a diagram illustrating an embodiment of a method that furtherdefines Step 120 of FIG. 5. This diagram shows a method performed by thebaseband processing module to convert the encoded data into streams ofsymbols in accordance with the number of transmit streams and the modeselect signal. Such processing begins at Step 122 where the basebandprocessing module interleaves the encoded data over multiple symbols andsubcarriers of a channel to produce interleaved data. In general, theinterleaving process is designed to spread the encoded data overmultiple symbols and transmit streams. This allows improved detectionand error correction capability at the receiver. In one embodiment, theinterleaving process will follow the IEEE 802.11(a) or (g) standard forbackward compatible modes. For higher performance modes (e.g., IEEE802.11(n), the interleaving will also be done over multiple transmitpaths or streams.

The process then proceeds to Step 124 where the baseband processingmodule demultiplexes the interleaved data into a number of parallelstreams of interleaved data. The number of parallel streams correspondsto the number of transmit streams, which in turn corresponds to thenumber of antennae indicated by the particular mode being utilized. Theprocess then continues to Steps 126 and 128, where for each of theparallel streams of interleaved data, the baseband processing modulemaps the interleaved data into a quadrature amplitude modulated (QAM)symbol to produce frequency domain symbols at Step 126. At Step 128, thebaseband processing module converts the frequency domain symbols intotime domain symbols, which may be done utilizing an inverse fast Fouriertransform. The conversion of the frequency domain symbols into the timedomain symbols may further include adding a cyclic prefix to allowremoval of intersymbol interference at the receiver. Note that thelength of the inverse fast Fourier transform and cyclic prefix aredefined in the mode tables of tables 1-12. In general, a 64-pointinverse fast Fourier transform is employed for 20 MHz channels and128-point inverse fast Fourier transform is employed for 40 MHzchannels.

The process then proceeds to Step 130 where the baseband processingmodule space and time encodes the time domain symbols for each of theparallel streams of interleaved data to produce the streams of symbols.In one embodiment, the space and time encoding may be done by space andtime encoding the time domain symbols of the parallel streams ofinterleaved data into a corresponding number of streams of symbolsutilizing an encoding matrix. Alternatively, the space and time encodingmay be done by space and time encoding the time domain symbols ofM-parallel streams of interleaved data into P-streams of symbolsutilizing the encoding matrix, where P=2M. In one embodiment theencoding matrix may comprise a form of:

$\quad\begin{bmatrix}C_{1} & C_{2} & C_{3} & C_{4} & \cdots & C_{{2M} - 1} & C_{2M} \\{- C_{2}^{*}} & C_{1}^{*} & {- C_{4}^{*}} & C_{3}^{*} & \cdots & {- C_{2M}^{*}} & C_{2,{M - 1}}\end{bmatrix}$

The number of rows of the encoding matrix corresponds to M and thenumber of columns of the encoding matrix corresponds to P. Theparticular symbol values of the constants within the encoding matrix maybe real or imaginary numbers.

FIGS. 7-9 are diagrams illustrating various embodiments for encoding thescrambled data.

FIG. 7 is a diagram of one method that may be utilized by the basebandprocessing module to encode the scrambled data at Step 116 of FIG. 5. Inthis method, the encoding of FIG. 7 may include an optional Step 144where the baseband processing module may optionally perform encodingwith an outer Reed-Solomon (RS) code to produce RS encoded data. It isnoted that Step 144 may be conducted in parallel with Step 140 describedbelow.

Also, the process continues at Step 140 where the baseband processingmodule performs a convolutional encoding with a 64 state code andgenerator polynomials of G₀=133₈ and G₁=171₈ on the scrambled data (thatmay or may not have undergone RS encoding) to produce convolutionalencoded data. The process then proceeds to Step 142 where the basebandprocessing module punctures the convolutional encoded data at one of aplurality of rates in accordance with the mode selection signal toproduce the encoded data. Note that the puncture rates may include 1/2,2/3 and/or 3/4, or any rate as specified in tables 1-12. Note that, fora particular, mode, the rate may be selected for backward compatibilitywith IEEE 802.11(a), IEEE 802.11(g), or IEEE 802.11(n) raterequirements.

FIG. 8 is a diagram of another encoding method that may be utilized bythe baseband processing module to encode the scrambled data at Step 116of FIG. 5. In this embodiment, the encoding of FIG. 8 may include anoptional Step 148 where the baseband processing module may optionallyperform encoding with an outer RS code to produce RS encoded data. It isnoted that Step 148 may be conducted in parallel with Step 146 describedbelow.

The method then continues at Step 146 where the baseband processingmodule encodes the scrambled data (that may or may not have undergone RSencoding) in accordance with a complimentary code keying (CCK) code toproduce the encoded data. This may be done in accordance with IEEE802.11(b) specifications, IEEE 802.11(g), and/or IEEE 802.11(n)specifications.

FIG. 9 is a diagram of yet another method for encoding the scrambleddata at Step 116, which may be performed by the baseband processingmodule. In this embodiment, the encoding of FIG. 9 may include anoptional Step 154 where the baseband processing module may optionallyperform encoding with an outer RS code to produce RS encoded data.

Then, in some embodiments, the process continues at Step 150 where thebaseband processing module performs LDPC (Low Density Parity Check)coding on the scrambled data (that may or may not have undergone RSencoding) to produce LDPC coded bits. Alternatively, the Step 150 mayoperate by performing convolutional encoding with a 256 state code andgenerator polynomials of G₀=561₈ and G₁=753₈ on the scrambled data thescrambled data (that may or may not have undergone RS encoding) toproduce convolutional encoded data. The process then proceeds to Step152 where the baseband processing module punctures the convolutionalencoded data at one of the plurality of rates in accordance with a modeselection signal to produce encoded data. Note that the puncture rate isindicated in the tables 1-12 for the corresponding mode.

The encoding of FIG. 9 may further include the optional Step 154 wherethe baseband processing module combines the convolutional encoding withan outer Reed Solomon code to produce the convolutional encoded data.

FIGS. 10A and 10B are diagrams illustrating embodiments of a radiotransmitter. This may involve the PMD module of a WLAN transmitter. InFIG. 10A, the baseband processing is shown to include a scrambler 172,channel encoder 174, interleaver 176, demultiplexer 178, a plurality ofsymbol mappers 180-184, a plurality of inverse fast Fourier transform(IFFT)/cyclic prefix addition modules 186-190 and a space/time encoder192. The baseband portion of the transmitter may further include a modemanager module 175 that receives the mode selection signal 173 andproduces settings 179 for the radio transmitter portion and produces therate selection 171 for the baseband portion. In this embodiment, thescrambler 172, the channel encoder 174, and the interleave 176 comprisean error protection module. The symbol mappers 180-184, the plurality ofIFFT/cyclic prefix modules 186-190, the space time encoder 192 comprisea portion of the digital baseband processing module.

In operations, the scrambler 172 adds (e.g., in a Galois Finite Field(GF2)) a pseudo random sequence to the outbound data bits 88 to make thedata appear random. A pseudo random sequence may be generated from afeedback shift register with the generator polynomial of S(x)=x⁷+x⁴+1 toproduce scrambled data. The channel encoder 174 receives the scrambleddata and generates a new sequence of bits with redundancy. This willenable improved detection at the receiver. The channel encoder 174 mayoperate in one of a plurality of modes. For example, for backwardcompatibility with IEEE 802.11(a) and IEEE 802.11(g), the channelencoder has the form of a rate 1/2 convolutional encoder with 64 statesand a generator polynomials of G₀=133₈ and G₁=171₈. The output of theconvolutional encoder may be punctured to rates of 1/2, 2/3, and 3/4according to the specified rate tables (e.g., tables 1-12). For backwardcompatibility with IEEE 802.11(b) and the CCK modes of IEEE 802.11(g),the channel encoder has the form of a CCK code as defined in IEEE802.11(b). For higher data rates (such as those illustrated in tables 6,8 and 10), the channel encoder may use the same convolution encoding asdescribed above or it may use a more powerful code, including aconvolutional code with more states, any one or more of the varioustypes of error correction codes (ECCs) mentioned above (e.g., RS, LDPC,turbo, TTCM, etc.) a parallel concatenated (turbo) code and/or a lowdensity parity check (LDPC) block code. Further, any one of these codesmay be combined with an outer Reed Solomon code. Based on a balancing ofperformance, backward compatibility and low latency, one or more ofthese codes may be optimal. Note that the concatenated turbo encodingand low density parity check will be described in greater detail withreference to subsequent Figures.

The interleaver 176 receives the encoded data and spreads it overmultiple symbols and transmit streams. This allows improved detectionand error correction capabilities at the receiver. In one embodiment,the interleaver 176 will follow the IEEE 802.11(a) or (g) standard inthe backward compatible modes. For higher performance modes (e.g., suchas those illustrated in tables 6, 8 and 10), the interleaver willinterleave data over multiple transmit streams. The demultiplexer 178converts the serial interleave stream from interleaver 176 intoM-parallel streams for transmission.

Each symbol mapper 180-184 receives a corresponding one of theM-parallel paths of data from the demultiplexer. Each symbol mapper180-182 lock maps bit streams to quadrature amplitude modulated QAMsymbols (e.g., BPSK, QPSK, 16 QAM, 64 QAM, 256 QAM, et cetera) accordingto the rate tables (e.g., tables 1-12). For IEEE 802.11(a) backwardcompatibility, double Gray coding may be used.

The map symbols produced by each of the symbol mappers 180-184 areprovided to the IFFT/cyclic prefix addition modules 186-190, whichperforms frequency domain to time domain conversions and adds a prefix,which allows removal of inter-symbol interference at the receiver. Notethat the length of the IFFT and cyclic prefix are defined in the modetables of tables 1-12. In general, a 64-point IFFT will be used for 20MHz channels and 128-point IFFT will be used for 40 MHz channels.

The space/time encoder 192 receives the M-parallel paths of time domainsymbols and converts them into P-output symbols. In one embodiment, thenumber of M-input paths will equal the number of P-output paths. Inanother embodiment, the number of output paths P will equal 2M paths.For each of the paths, the space/time encoder multiples the inputsymbols with an encoding matrix that has the form of

$\quad{\begin{bmatrix}C_{1} & C_{2} & C_{3} & C_{4} & \cdots & C_{{2M} - 1} & C_{2M} \\{- C_{2}^{*}} & C_{1}^{*} & {- C_{4}^{*}} & C_{3}^{*} & \cdots & {- C_{2M}^{*}} & C_{2,{M - 1}}\end{bmatrix}.}$

The rows of the encoding matrix correspond to the number of input pathsand the columns correspond to the number of output paths.

FIG. 10B illustrates the radio portion of the transmitter that includesa plurality of digital filter/up-sampling modules 194-198,digital-to-analog conversion modules 200-204, analog filters 206-216,I/Q modulators 218-222, RF amplifiers 224-228, RF filters 230-234 andantennae 236-240. The P-outputs from the space/time encoder 192 arereceived by respective digital filtering/up-sampling modules 194-198. Inone embodiment, the digital filters/up sampling modules 194-198 are partof the digital baseband processing module and the remaining componentscomprise the plurality of RF front-ends. In such an embodiment, thedigital baseband processing module and the RF front end comprise adirect conversion module.

In operation, the number of radio paths that are active correspond tothe number of P-outputs. For example, if only one P-output path isgenerated, only one of the radio transmitter paths will be active. Asone of average skill in the art will appreciate, the number of outputpaths may range from one to any desired number.

The digital filtering/up-sampling modules 194-198 filter thecorresponding symbols and adjust the sampling rates to correspond withthe desired sampling rates of the digital-to-analog conversion modules200-204. The digital-to-analog conversion modules 200-204 convert thedigital filtered and up-sampled signals into corresponding in-phase andquadrature analog signals. The analog filters 208-214 filter thecorresponding in-phase and/or quadrature components of the analogsignals, and provide the filtered signals to the corresponding I/Qmodulators 218-222. The I/Q modulators 218-222 based on a localoscillation, which is produced by a local oscillator 100, up-convertsthe I/Q signals into radio frequency signals.

The RF amplifiers 224-228 amplify the RF signals which are thensubsequently filtered via RF filters 230-234 before being transmittedvia antennae 236-240.

FIGS. 11A and 11B are diagrams illustrating embodiments of a radioreceiver. These diagrams illustrate a schematic block diagram of anotherembodiment of a receiver. FIG. 11A illustrates the analog portion of thereceiver which includes a plurality of receiver paths. Each receiverpath includes an antenna, RF filters 252-256, low noise amplifiers258-260, I/Q demodulators 264-268, analog filters 270-280,analog-to-digital converters 282-286 and digital filters anddown-sampling modules 288-290.

In operation, the antennae receive inbound RF signals, which areband-pass filtered via the RF filters 252-256. The corresponding lownoise amplifiers 258-260 amplify the filtered signals and provide themto the corresponding I/Q demodulators 264-268. The I/Q demodulators264-268, based on a local oscillation, which is produced by localoscillator 100, down-converts the RF signals into baseband in-phase andquadrature analog signals.

The corresponding analog filters 270-280 filter the in-phase andquadrature analog components, respectively. The analog-to-digitalconverters 282-286 convert the in-phase and quadrature analog signalsinto a digital signal. The digital filtering and down-sampling modules288-290 filter the digital signals and adjust the sampling rate tocorrespond to the rate of the baseband processing, which will bedescribed in FIG. 11B.

FIG. 11B illustrates the baseband processing of a receiver. The basebandprocessing includes a space/time decoder 294, a plurality of fastFourier transform (FFT)/cyclic prefix removal modules 296-300, aplurality of symbol demapping modules 302-306, a multiplexer 308, adeinterleaver 310, a channel decoder 312, and a descramble module 314.The baseband processing module may further include a mode managingmodule 175, which produces rate selections 171 and settings 179 based onmode selections 173. The space/time decoding module 294, which performsthe inverse function of space/time encoder 192, receives P-inputs fromthe receiver paths and produce M-output paths. The M-output paths areprocessed via the FFT/cyclic prefix removal modules 296-300 whichperform the inverse function of the IFFT/cyclic prefix addition modules186-190 to produce frequency domain symbols.

The symbol demapping modules 302-306 convert the frequency domainsymbols into data utilizing an inverse process of the symbol mappers180-184. The multiplexer 308 combines the demapped symbol streams into asingle path.

The deinterleaver 310 deinterleaves the single path utilizing an inversefunction of the function performed by interleaver 176. The deinterleaveddata is then provided to the channel decoder 312 which performs theinverse function of channel encoder 174. The descrambler 314 receivesthe decoded data and performs the inverse function of scrambler 172 toproduce the inbound data 98.

FIG. 12 is a diagram illustrating an embodiment of an access point (AP)and multiple wireless local area network (WLAN) devices operatingaccording to one or more various aspects and/or embodiments of theinvention. The AP point 1200 may compatible with any number ofcommunication protocols and/or standards, e.g., IEEE 802.11(a), IEEE802.11(b), IEEE 802.11(g), IEEE 802.11(n), as well as in accordance withvarious aspects of invention. According to certain aspects of thepresent invention, the AP supports backwards compatibility with priorversions of the IEEE 802.11x standards as well. According to otheraspects of the present invention, the AP 1200 supports communicationswith the WLAN devices 1202, 1204, and 1206 with channel bandwidths, MIMOdimensions, and at data throughput rates unsupported by the prior IEEE802.11x operating standards. For example, the access point 1200 and WLANdevices 1202, 1204, and 1206 may support channel bandwidths from thoseof prior version devices and from 40 MHz to 1.28 GHz and above. Theaccess point 1200 and WLAN devices 1202, 1204, and 1206 support MIMOdimensions to 4×4 and greater. With these characteristics, the accesspoint 1200 and WLAN devices 1202, 1204, and 1206 may support datathroughput rates to 1 GHz and above.

The AP 1200 supports simultaneous communications with more than one ofthe WLAN devices 1202, 1204, and 1206. Simultaneous communications maybe serviced via OFDM tone allocations (e.g., certain number of OFDMtones in a given cluster), MIMO dimension multiplexing, or via othertechniques. With some simultaneous communications, the AP 1200 mayallocate one or more of the multiple antennae thereof respectively tosupport communication with each WLAN device 1202, 1204, and 1206, forexample.

Further, the AP 1200 and WLAN devices 1202, 1204, and 1206 are backwardscompatible with the IEEE 802.11(a), (b), (g), and (n) operatingstandards. In supporting such backwards compatibility, these devicessupport signal formats and structures that are consistent with theseprior operating standards. With the structure of FIG. 13, the accesspoint enacts OFDMA cluster parsing to support MU-MIMO. With thestructure and operation of FIG. 13, data intended for each user may beencoded separately. The structure of FIG. 13 supports K users, withdetail shown for the Kth user. Cn is the cluster number. Generally,operation of such structure is described with the following equations:

$T = {\sum\limits_{c = 1}^{N_{c}}{S(c)}}$${S(c)} = {{\sum\limits_{i = 1}^{N_{ss}{(c)}}{{s\left( {i_{ss},c} \right)}{s\left( {i_{ss},c} \right)}}} = {\max \left\{ {1,\frac{N_{BPSCS}\left( i_{ss} \right)}{2}} \right\}}}$

FIG. 13A is a diagram illustrating an embodiment of a structure employedby an access point (or WLAN) device supporting orthogonal frequencydivision multiple access (OFDMA) cluster parsing. In a multi-userembodiment, each user is encoded separately. This diagram shows encodingand interleaving for only one user. When multiple encoders are employedfor a single user, scrambled bits are assigned to various respectiveencoders in a round robin fashion on a per bit basis. The cluster parser(in accordance with performing spatial multiplexing) allocates encodedbits to clusters assigned to the same user. Generally speaking, acluster is a depiction of the mapping of tones, such as for an OFDMsymbol, within or among one or more channels (e.g., sub-divided portionsof the spectrum) that may be situated in one or more bands (e.g.,portions of the spectrum separated by relatively larger amounts). As anexample, various channels of 80 MHz may be situated within or centeredaround a 5 GHz band. The channels within any such band may be continuous(e.g., adjacent to one another) or discontinuous (e.g., separated bysome guard interval or band gap). Oftentimes, one or more channels maybe situated within a given band, and different bands need notnecessarily have a same number of channels therein.

In the equation shown above, s(i_(ss),c) is the number of coded bits perdimension on the i_(ss)'th spatial stream of cluster c. The value, S(c),is the sum of s(i_(ss),c) over all spatial streams in cluster c and T isthe sum of S(c) over all clusters. Consecutive blocks of S(c) bits areassigned to different clusters in a round robin fashion. If multipleencoders are used, T consecutive encoded bits from a single encoder areused for one round robin cycle across the clusters. Operating together,the different encoders are used in a round robin fashion. For example, afirst group of consecutive bits generated by a first encoder areallocated across the clusters (e.g., a first group of those consecutivebits going to a first cluster, then a second group of those consecutivebits going to a second cluster, and so on until the first group ofconsecutive bits are all employed). Then, a second group of consecutivebits generated by a second encoder are allocated across the clusters(continuing from where the first group of consecutive bits had ended).This process continues across all of the encoders and will return backto the first encoder after processing the consecutive bits generated bythe last encoder in the group.

Various embodiments may operate in accordance with stream parsing thatis in accordance with the IEEE 802.11n specification. Each of therespective stream parsers allocates bits within a cluster to spatialstreams in accordance with the IEEE 802.11n specification. Each spatialstream is frequency interleaved according to 20 MHz interleavercorresponding to a frame type for the respective user. Again, thisdiagram shows encoding and interleaving for only one user.

FIG. 13B is a diagram illustrating an embodiment of a structure employedby an access point (or WLAN) device supporting multi-user OFDMA(MU-OFDMA). Again, as described above, each user is encoded separately.Whereas the previous diagram shows encoding and interleaving for onlyone user, this diagram shows, in each layer, encoding and interleavingfor one user (Same as previous slide for each user). However, themultiple layers then correspond to multiple users. The beamformingmatrix V_(iCj) may be found to maximize the aggregate capacity for allusers, where i is a user index and Cj is a cluster index. The size ofV_(iCj) is Nt_(Ci)×Nsts_(i) where Nt_(Ci) is the number of transmitantennae for cluster C_(i) and Nsts_(i) is the number of space-timestream for user i. The transmit antennae for each cluster is conceptual:operating at carrier frequency for cluster C_(i). Physically, n_(Ci)^(th) transmit antenna for cluster Ci may be shared with m_(Cj) ^(th)transmit antenna for cluster Cj. The cluster parser allocates encodedbits to clusters assigned to the same user, where s(i_(ss),c) is thenumber of coded bits per dimension on the i_(ss)'th spatial stream ofcluster c.

Analogous to the previous embodiment, the value, S(c), is the sum ofs(i_(ss),c) over all spatial streams in cluster c and T is the sum ofS(c) over all clusters. Consecutive blocks of S(c) bits are assigned todifferent clusters in a round robin fashion. If multiple encoders areused, T consecutive encoded bits from different encoders are used in around robin fashion. Various embodiments may operate in accordance withstream parsing that is in accordance with the IEEE 802.11nspecification. Each of the respective stream parsers allocates bitswithin a cluster to spatial streams in accordance with the IEEE 802.11nspecification. Each spatial stream is frequency interleaved according to20 MHz interleaver corresponding to a frame type for the respectiveuser.

The structure employed within FIG. 13A and alternatively, FIG. 13B,includes at least one encoder for encoding one or more information bitsthereby generating coded bits. Again, any of a variety of ECCs may beemployed by the at least one encoder, and different ECCs may be employedfor different of the encoders. Moreover, various of the encoders mayoperate not only in accordance with different ECCs, but may have otherdifferent operational parameters such as different code rates, etc. Theone or more cluster parsers are implemented for assigning the coded bitsamong various clusters corresponding to the various wirelesscommunication devices to which communications are to be made. Forexample, a cluster mapping provides an assignment of the coded bitsbased on the particular wireless communication devices to whichcommunications are to be made. The antennae of the transmitting deviceare for transmitting the coded bits, using the plurality of clusters, tothe plurality of wireless communication devices.

There are a variety of means by which the coded bits may be assignedamong the clusters. For example, a first subset of the coded bits may beassigned among a first cluster, and a second subset of the coded bitsmay be assigned among a second cluster. A first subset of the antennaeoperate by transmitting the first subset of coded bits, using the firstcluster, to a first wireless communication device, and a second subsetof the antennae operate by transmitting the second subset of coded bits,using the second cluster, to a second wireless communication device. Thevarious subsets of the antennae may include one or more common antennae(e.g., one of the antennae may be in more than one subset employed fortransmitting signals).

Alternatively, a first subset of the coded bits may be assigned among afirst group of clusters (e.g., more than one cluster), and a secondsubset of the coded bits may be assigned among a second group ofclusters (e.g., also more than one cluster). In such an instance, thetransmitting communication device may include the stream parsers forallocating the first subset of coded bits to a first spatial stream andallocating the second subset of coded bits to a second spatial stream.Respective subsets of the antennae may be employed for each of thespatial streams (e.g., a first subset of the antennae for transmittingthe first spatial stream, and a second subset of the antennae fortransmitting the second spatial stream). Also, the various subsets ofcoded bits need not have identical number of bits.

The various clusters employed for communications may be varied innature. For example, a cluster may be composed with as few as onechannel within one band. Alternatively, a cluster may be composed with afirst channel in a first band and a second channel in a second band. Acluster may alternatively be composed with a first number of channels ina first band and a second band and a second number of channels in athird band and a fourth band. In some instances, the third band is thefirst band, and the fourth band is the second band.

With the structure of FIG. 13B, an AP may simultaneously transmit amulti-user multiple input multiple output (MU-MIMO) and/or orthogonalfrequency division multiple access (OFDMA) frame (alternatively,referred to as packet) to a plurality of WLAN devices.

In some embodiments, acknowledgement (ACK) of these respectivetransmissions within such an MU-MIMO and/or OFDMA frame must be receivedfrom each WLAN device. Several of the following diagrams and relatedwritten description describe embodiments for acknowledgement for suchtransmissions. The transmissions may be OFDMA, MU-MIMO or MU-MIMO/OFDMA.OFDM is a subset of OFDMA when a single user transmits at a given time.MIMO also includes SISO, SIMO, and MISO. OFDMA clusters may becontinuous or discontinuous. Transmissions on different OFDMA clustersmay be simultaneous or non-simultaneous. Any communication device may becapable of supporting a single cluster or multiple clusters. Again, acluster may be composed on one or more channels within or among one ormore bands. A cluster may be as few as a single channel within a singleband.

A MU-MIMO/OFDMA capable transmitter (e.g., an AP) may transmit packetsto more than one wireless station (STA) on a same cluster in a singleaggregated packet (in accordance with time multiplexing). Channelcharacterization and training may be performed for each of the differentcommunication channels corresponding to the various respective wirelesscommunication devices (e.g., STAs).

Generally, some data transmissions may be targeted for reception bymultiple individual receivers—e.g. MU-MIMO and/or OFDMA transmissions,which are different than single transmissions with a multi-receiveraddress. For example, a single OFDMA transmission uses different tonesor sets of tones (e.g., clusters or channels) to send distinct sets ofinformation, each set of set of information transmitted to one or morereceivers simultaneously in the time domain. Again, an OFDMAtransmission sent to one user is equivalent to an OFDM transmission. Asingle MU-MIMO transmission may include spatially-diverse signals over acommon set of tones, each containing distinct information and eachtransmitted to one or more distinct receivers. Some single transmissionsmay be a combination of OFDMA and MU-MIMO. MIMO transceivers illustratedmay include SISO, SIMO, and MISO transceivers. Transmissions ondifferent OFDMA clusters may be simultaneous or non-simultaneous. Legacyusers and new version users (e.g., TGac MU-MIMO, OFDMA, MU-MIMO/OFDMA,etc.) may share bandwidth at a given time or they can be scheduled atdifferent times for certain embodiments.

The intended receivers of the MU-MIMO/OFDMA transmissions need torespond to the transmitter an acknowledgement (e.g. either a singleacknowledgement or a block acknowledgement may be provided).Acknowledgements need to be separated at the receiver, the separationperformed through any of several means, or combinations of these means:temporally divided, frequency divided, code divided, e.g. multi-userprecoding. For temporal separation, a scheme to define the time slottingis required, which may be slotted, polled, or a combination thereof. Anyacknowledgement scheme may, if desired, have an option forreverse-data-aggregation such that data may be combined with an ACK.Hereinafter, the terms “ACK”, “acknowledgement”, and “BA” are all meantto be inclusive of either ACK or BA (block acknowledgement). Forexample, even if only one or ACK or BA is specifically referenced, suchembodiments may be equally adapted to any of ACK or BA.

Different embodiments of ACK operations may be made in accordance withtime slotted ACK transmissions or time scheduled ACK transmissions.

A first embodiment of ACK operations is to have time slotted ACKtransmissions. Such embodiment may include an assignment of an order forclusters used for the data transmission such that ACK responses areordered according to the cluster order, e.g. one slot of time for eachcluster. The intended receivers respond in the order provided at fixedtime points that are known separately from information that is conveyedwithin the MU-MIMO/OFDMA transmission (e.g., information regarding thesize of each slot is exchanged, or they respond in the ordered sequencebased on the detection of the respondents ACK transmissions).

This embodiment works well for OFDMA, but may be slightly morecomplicated for the combination of OFDMA and MU-MIMO. For such anOFDMA/MU-MIMO combination, receiving devices within a cluster areordered. Such ordering is required when the data transmitter is SU-MIMOreceiver, but is less efficient in such operations because there will beno ACKs on some clusters but not others. Such is the case because someclusters may have no transmission while other clusters are grouped butreceiving devices are unaware of the absence of data for “other”clusters, so they still wait their turn to send and ACK for the cluster,even when no ACK is required for “missing” transmissions correspondingto the previous slot. This inefficiency can be avoided if the datatransmitter does not schedule a time for clusters having no datatransmitted, e.g., the transmitter may require an explicit signaling ofwhich clusters have been used during this data transmission so thatlater users know that they do not need to wait for an ACK for a clusterthat does not need one.

A second embodiment of ACK operations is to have time scheduled ACKtransmissions. Such an embodiment may include an assignment of a set ofspecific times for clusters used for the data transmission such that ACKresponses are transmitted according to the set of specific times (e.g.,one start time and one end time for each cluster). The intendedreceivers respond according to the start and end times provided.

According to some aspects presented herein, the data and the ACKtransmissions are protected by the network allocation vector (NAV), sono CSMA (Carrier Sense Multiple Access) is needed between thetransmission of the data and ACKs. In such case, the data transmittermay specify either time for the ACK per cluster and the cluster to usefor ACK transmission or a slotted order for the ACK transmissions. Insuch instances, the data transmitter knows the data transmission timeand knows the BA (e.g., ACK) size, so it can accurately schedule a timefor each receiver's ACK or BA, or provide an ordering for eachreceiver's ACK or BA knowing that the slot time is fixed through someother exchange of information regarding the size of the slots, orknowing that the slot time has an upper bound based on the duration ofthe ACK transmission. The scheduled transmission time for the ACK can beaggregated with data and transmitted with the data transmission. Thescheduling information may be located within the MU-MIMO/OFDMAtransmission as a separate control or management frame and may containduration information that determines if aggregation of acknowledgementswith data is permitted. The OFDMA/MU-MIMO data transmitter may assignthe ACK for data to appear on the cluster on which it has transmittedthat data in order to avoid cluster switching by the receiving device.Time slotted and scheduled acknowledgements reduce collision overheadcompared to a scheme that employs CSMA-determined ACK responses.

FIG. 14A is a diagram illustrating an embodiment of a structure used forconveyance of scheduled or slotted start time within an orthogonalfrequency division multiple access (OFDMA)/multi-user multiple inputmultiple output (MU-MIMO) frame as media access control (MAC) frames.The time slotted acknowledgement information is contained in MAC Headersthat are part of the OFDMA/MU-MIMO transmission. Multiple MAC framesexist according to MU-MIMO and OFDMA dimensions of the transmission.Each MAC frame has information unique and specific to the receiversapplicable for those dimensions.

With such structure: AID=STA identifier (e.g. 11-bit associationidentifier AID); Sack_end=STA scheduled acknowledgement slot end time,first start time begins at end of OFDMA/MU-MIMO packet reception; andSack_clusters=Scheduled acknowledgement cluster assignment, e.g. set ofclusters for acknowledgement, and the duration of the acknowledgementtime slot is previous Sack_end time to this Sack_end time. The SAC fieldcan occur in multiple MAC frames within the OFDMA/MU-MIMO frame, e.g.,zero or once or multiple times for any given RA.

FIG. 14B is a diagram illustrating an embodiment of a structure used forindicating multiple SACK fields in one MAC frame. This is anotherdiagram illustrating a structure used for conveyance of slotted starttime within an OFDMA/MU-MIMO frame as MAC frames. The structure of FIG.14B is similar to that of FIG. 14A. With the structure of FIG. 14B, theSACK field may occur multiple times within a single frame, e.g., ifmultiple recipients are sent frames sequentially within a singlecluster. In such case, the MAC header field (e.g., NSACK) indicates thenumber of SACK fields that will appear and each SACK field needs to beaccompanied by an AID or 48-bit MAC address. In such case, each SIDcontains an AID or 48-bit address. The SACK field structure previouslydescribed may be employed and the SID+SACK may be repeated NSACK times.

FIG. 14C is a diagram illustrating an alternative embodiment of astructure used for indicating multiple SACK fields in one MAC frame.With the structure of FIG. 14C, the SAC can occur as an independent MACframe, which contains mostly only the SACK field—that is, no MAC payloadas in the case of an IEEE 802.11 control type frame.

FIG. 15 is a diagram illustrating an embodiment of a structure used forthe conveyance of start time within an OFDMA/MU-MIMO frame as a PHYHeader extension. The acknowledgement information is contained inmultiple PHY Header extension fields that exist for OFDMA and MU-MIMOdimensions. Multiple PHY Header extension fields exist according toMU-MIMO and OFDMA dimensions of the transmission. Each MAC frame hasinformation unique and specific to the receivers applicable for thosedimensions.

With such structure: AID=STA identifier (e.g. 11-bit associationidentifier AID); Sack_end=STA scheduled acknowledgement slot end time,first start time begins at end of OFDMA/MU-MIMO packet reception; andSack_clusters=Scheduled acknowledgement cluster assignment, e.g. set ofclusters for acknowledgement, and the duration of the acknowledgementtime slot is previous Sack_end time to this Sack_end time.

Many of the following diagrams show coordination and scheduling usingvarious means (e.g., time-slotted, polling, etc.) by which the varioususers in a multi-user communication system may provide their respectiveacknowledgements (ACKs) back to the transmitting communication device(e.g., an AP that makes a transmission to wireless stations (STAs)).

Generally speaking, various aspects of the invention are directed to acommunication device (e.g., an AP in some instance) including a basebandprocessing module for generating a multi-user frame. Such a multi-userpacket may be a multiple input multiple output (MU-MIMO) packet, anorthogonal frequency division multiple access (OFDMA) packet, or aMU-MIMO/OFDMA packet. It is of course noted that various othercomponents may be interveningly coupled between such a circuitry and/ormodule that generates such a multi-user frame and at least one antennawithin the wireless communication device. The transmitting wirelesscommunication device employs at least one antenna for transmitting themulti-user packet to a number of wireless communication devices. Inresponse to the multi-user packet, the wireless communication deviceoperates by receiving respective acknowledgements (ACKs) from all or asubset of the wireless communication devices to which the multi-userpacket has been sent. The multi-user packet that is transmitted to thewireless communication devices includes ACK instructions correspondingrespectively to each of the wireless communication devices. In otherwords, in one instance, the multi-user packet itself includes timeslotting for the wireless communication devices to provide theirrespective ACK to the transmitting communication device. Alternatively,polling may be provided from the transmitting wireless communicationdevice to give explicit directions to each of the receiving wirelesscommunication devices regarding the manner in which its respective ACKis to be provided.

Such ACK instructions may direct a variety of parameters by which theACKs are to be provided (e.g., the order among the wirelesscommunication devices by which the ACKs are to be provided, the one ormore clusters to be employed by each of the wireless communicationdevices when making an ACK, the cluster assignments themselves among thevarious wireless communication devices). Depending on the receivecapability of the transmitting wireless communication device and itscapability to receive the ACKs, the ACKs may be provided sequentially(serially) or simultaneously and in parallel (e.g., of the transmittingwireless communication device has MU-MIMO and/or OFDMA receivecapability).

The various wireless communication devices to which the multi-userpacket is transmitted may be a mix of different types of wirelesscommunication devices, including legacy wireless communication devices,and also including MU-MIMO and/or OFDMA compatible wirelesscommunication devices.

FIGS. 16 and 17 are signal diagrams illustrating embodiments of timeslotted/scheduled acknowledgements showing network allocation vector(NAV) protection for acknowledgements. A request to send (RTS) is sentfrom STA0, onto each of the clusters shown, clusters 1, 2, 3, 4. STA1responds with a clear to send (CTS) transmission on cluster 1. An OFDMAdata transmission is made to multiple STAs on clusters 1, 2, 3, 4. Thecontents thereof are frequency separated. While this particularembodiment shows an OFDMA data transmission, the data transmission mayalternatively be a MU-MIMO data transmission, or an OFDMA/MU-MIMO datatransmission. It is also noted that these specific examples andembodiments are not exhaustive, and the principles described herein maybe adapted to accommodate any desired configuration and manner ofproviding ACKs.

STA1 receives and transmits on cluster 1, STA2 receives and transmits oncluster 2, STA3 receives and transmits on cluster 3, and STA4 receivesand transmits on cluster 4. Referring to FIG. 17, STA1 receives andtransmits on cluster 1, STA2 receives on cluster 2 and transmits oncluster 1, STA3 receives on cluster 3 and transmits on cluster 1, andSTA4 receives on cluster 4 and transmits on cluster 1. In other words,all of the STAs provide their respective ACKs on the same cluster.

In these and other diagrams, the OFDMA separation may be seen among thevarious respective clusters employed by the different transmissionsrelated to different STAs.

FIG. 18 is a signal diagram illustrating an embodiment of time slottedor scheduled acknowledgements that are transmitted in multiple clusters.With this signal diagram, STA1 has the capability to receive andtransmit on clusters 1, 2, and 4, and in the diagram, receivesinformation on cluster 1 and transmits an ACK on clusters 1, 2, and 4.STA2 receives on cluster 2 and transmits on clusters 1, 2, 3, and 4(i.e., all of the clusters). STA3 receives on cluster 3 and transmits onclusters 2, 3, 4. STA4 receives on cluster 4 and transmits on cluster 1.

FIG. 19 is a signal diagram illustrating an embodiment of time slottedor scheduled acknowledgements that are transmitted in multiple clusterswhen a cluster is not in use. For example, this diagrams shows that oneof the clusters is not used the transmitter during the MU-MIMO datatransmission (i.e., cluster 2 carries no part of the MU-MIMO datatransmission). With this signal diagram, STA1 receives and transmits oncluster 1, STA2 does not receive any data in the OFDMA transmission,STA3 receives and transmits on cluster 3, and STA4 receives andtransmits on cluster 4.

FIG. 20 is a signal diagram illustrating an embodiment of fixedacknowledgement slotting. With the example of FIG. 20, STA1 receives andtransmits on cluster 1, STA2 does not receive any data in the OFDMAtransmission, STA3 receives and transmits on cluster 3, and STA4receives and transmits on cluster 4. In this diagram, there is a timethat would potentially be wasted with no transmission made there.

FIGS. 21, 22, 23, 24, 25, 26, 27, 28, and 29 are signal diagramsillustrating embodiments of time slotted or scheduled acknowledgementsequences when one or more STAs share channel (e.g., OFDMA and/orMU-MIMO).

FIG. 21 is a signal diagram illustrating a time slotted acknowledgementsequence when a STA shares clusters. With this signal diagram, STA1receives on clusters 1 and 2 and transmits on cluster 1, STA2 canreceive on cluster 2, but in this case, there is no packet for STA2 oncluster 2, STA3 receives and transmits on cluster 3, and STA4 receivesand transmits on cluster 4.

FIG. 22 is a signal diagram illustrating a time slotted acknowledgementsequence when STAs shares clusters (e.g., OFDMA and MU-MIMO). With thissignal diagram, STA1 receives on clusters 1 and 2 and transmits oncluster 1, STA2 does not receive any data in the MU-MIMO/OFDMAtransmission, STA3 and STA4 receive and transmit on cluster 3, and STA5receives on cluster 4 and transmits on clusters 1, 2, 3, and 4. Thisdiagram shows one spatial respective dimension for each of STA3 and STA4existing within one of the clusters (e.g., cluster 3), for a total oftwo spatial dimensions used by the MU-MIMO/OFDMA data transmissionwithin cluster 3.

When the MU-MIMO/OFDMA data transmitter is limited to SU-MIMO receivecapability (i.e., does not include simultaneous receive capability),then a single RF Front End on the data transmitter (SU-MIMO) is employedfor reception. If MU-MIMO is used for the data transmission, thenrecipients may transmit the ACKs to the data transmitter sequentially(e.g., one at a time). Again, for the combination of OFDMA and MU-MIMOdata transmission, the ACKs must be made sequential across both thecluster and spatial domains as described and shown previously.

However, there may be instances when a MU-MIMO/OFDMA data transmitteralso has OFDMA/MU-MIMO receive capability. Such an embodiment wouldinclude a data transmitter having parallel RF Front Ends andsimultaneous multipacket reception capability. The ACK transmission onindividual clusters and also on multiple clusters may both be scheduledsimultaneously as described later herein when, for example, thetransmitting communication device (e.g., AP) has simultaneous receivecapability.

Time slotted or scheduled operation offers complete flexibility for allcombinations of OFDMA/MU-MIMO capabilities at receivers andtransmitters.

FIGS. 23, 24, 25, 26, 27, and 28 are signal diagrams illustratingvarious examples of time slotted or scheduled ACK reception.

FIG. 23 illustrates an ACK scheduling example for OFDMA receivecapability at an MU-MIMO data transmitter. This diagram shows that thetransmitting device has simultaneous receive capability (i.e., canreceive two or more ACKs at the same time, so two or more STAs can sendtheir respective ACKs simultaneously or in parallel with one another).With the example of FIG. 23, STA1 receives on clusters 1, and 2, andtransmits on clusters 1, and 2. STA2 does not receive any data in theMU-MIMO/OFDMA transmission. STA3 receives on cluster 3, and transmits oncluster 3. STA4 receives on cluster 3, and transmits on cluster 3. STA5receives on cluster 4 and transmits on cluster 4. As describedelsewhere, the Sack_clusters field needs to indicate the ordering ofwhich STAs are to send back their respective ACKs, and in this case of amultiple simultaneous reception capability at the MU-MIMO datatransmitter, all ACKs are scheduled for the same time, but on differentclusters and/or spatial streams.

FIG. 24 illustrates a time scheduled ACK sequence with multi-clusterMU-MIMO data transmission, showing in particular ACK scheduling forOFDMA receive capability at a MU-MIMO data transmitter. With the exampleof FIG. 24, STA1 receives on clusters 1, 2, 3, and 4 and transmits oncluster 1. STA2 receives on clusters 1, 2, 3, and 4 and transmits oncluster 2. STA3 receives on clusters 1, 2, 3, and 4 and transmits oncluster 3. STA4 receives on clusters 1, 2, 3, and 4 and transmits oncluster 4. This diagram shows a 4 clusters wide frame and eachrespective STA is directed to ACK on a separated and respective clusterat the same time.

FIG. 25 illustrates a time slotted or scheduled ACK sequence withmulti-cluster MU-MIMO data transmission. With example of FIG. 25, STA1receives on clusters 1, 2, 3, and 4 and transmits on clusters 1, 2, 3,and 4 (all clusters), STA2 receives on clusters 1, 2, 3, and 4 andtransmits on clusters 1, 2, 3, and 4 (all clusters), STA3 receives onclusters 1, 2, 3, and 4 and transmits on clusters 2 and 3, and STA4receives on clusters 1, 2, 3, and 4 and transmits only on cluster 4.

FIG. 26 illustrates a time slotted or scheduled ACK sequence with STAssharing clusters, e.g., OFDMA+MU-MIMO. FIG. 26 shows in particular anACK scheduling example for MU-MIMO/OFDMA receive capability of anMU-MIMO/OFDMA data transmitter. With the example of FIG. 26, STA1 hasOFDMA receive capability and receives separate frames on clusters 1 and2 and transmits on clusters 1 and 2, STA2 does not receive any data inthe MU-MIMO/OFDMA transmission, STA3 and STA4 receive and transmit oncluster 3, and STA5 receives and transmits on cluster 4.

FIG. 27 illustrates a time slotted or scheduled ACK sequence with STAssharing clusters, e.g., OFDMA+MU-MIMO. FIG. 27 shows in particular anACK scheduling example for MU-MIMO/OFDMA receive capability of anMU-MIMO/OFDMA data transmitter. With the example of FIG. 27, STA1 hasOFDMA receive capability and receives separate frames on clusters 1 and2 and transmits separate ACKs for the separate frames on clusters 1 and2. STA2 also receives on cluster 2 and transmits on cluster 2. As can beseen, Cluster 2 is employed for receiving for both STA1 and STA2. STA3and STA4 receive and transmit on cluster 3, and STA5 receives andtransmits on cluster 4. STA3 and STA4 also have MU-MIMO separation(e.g., spatial separation) within cluster 3. Within the sequencedepicted in FIG. 27, the MU-MIMO/OFDMA data transmitter can schedule theACK transmissions for STA3 and STA4 to be sequential, for example,within cluster 3 instead of in parallel as shown.

FIG. 28 illustrates a time slotted or scheduled ACK sequence with STAssharing clusters, e.g., OFDMA+MU-MIMO. FIG. 28 shows in particular anACK scheduling example for MU-MIMO/OFDMA receive capability of anMU-MIMO/OFDMA data transmitter. With the example of FIG. 28, STA1receives on clusters 1 and 2 and transmits on clusters 1 and 2. STA2receives on clusters 1 and 2 and transmits on clusters 1, 2, 3, and 4.STA3 and STA4 receive and transmit on cluster 3, and STA5 receives andtransmits on cluster 4. STA3 and STA4 also have MU-MIMO separation(e.g., spatial separation) within cluster 3.

FIG. 29 illustrates a time slotted ACK sequence, in particular an ACKscheduling example for MU-MIMO receive capability of an MU-MIMO datatransmitter. With the example of FIG. 29, STA1 receives on clusters 1,2, 3, and 4 and transmits on clusters 1 and 2. STA2 receives on clusters1, 2, 3, and 4 and transmits on clusters 1, 2, 3, and 4. STA3 receiveson clusters 1, 2, 3, and 4 and transmits on cluster 3. STA4 receives onclusters 1, 2, 3, and 4 and transmits on cluster 3. STA5 receives onclusters 1, 2, 3, and 4 and transmits on cluster 4.

FIGS. 30, 31, and 32 are signal diagrams illustrating variousembodiments of polled ACK operations of transmitting and receiving WLANdevices.

Additional embodiments may operate in accordance with polling of thevarious receivers (e.g., STAs) to request their respective ACKs. Forexample, an OFDMA frame may be employed to give explicit pollinginformation to the STAs for the transmitting device (e.g., AP) then toretrieve the respective ACKs there from. For example, the datatransmitter (e.g., AP) then follows data transmission of OFDMA/MU-MIMOwith polling of the receivers (e.g., STAs). The data transmitter (e.g.,AP) may poll more than one recipient at a time (i.e. OFDMA/MU-MIMO pollframe, OFDMA Poll frame, MU-MIMO poll frame, OFDM Poll frame, othercombination, etc.). Employing such polling functionality may operate toreduce collision overhead versus a scheme that allows carrier sensemultiple access (CSMA)-determined ACK responses. Such polling mayeliminate the need for explicit ACK transmission parameters (e.g., ACKtransmission timing and ACK transmission cluster assignment) that wouldhave been placed within the SACK field of PHY headers or MAC headers ofthe data transmissions had polling not been employed. Some of the ACKtransmission parameters (e.g., ACK transmission cluster assignment) maystill be provided within a poll frame.

Receiving devices respond to polls with ACK information. Theseoperations may combine reverse direction DATA with ACK information inresponse to a poll, which saves on overhead and increases throughput.Further, these operations allow the data transmitter to controlvariables to meet quality of service (QoS) scheduling goals becausethese operations allow the OFDMA/MU-MIMO data transmitter to controlreverse direction traffic timing. With these operations, polledACK/reverse data may be transmitted on different cluster(s). More thanone cluster may be used to transmit the reverse data, as per permissionfrom poll frame. A responder's combined ACK and reverse datatransmission may be done on clusters that were not used to transmit datato that responder. Multiple ACKs may be received simultaneously if thePoll frame was to multiple receivers. Such operation requires that datatransmitter (e.g., AP) supports multiple simultaneous reception (i.e.OFDMA/MU-MIMO reception).

The data transmitter may specify a single cluster to transmit thecombined ACK and reverse data. Information may be relayed on a singlecluster to all recipients which requires all recipients to switch tothat cluster at, for example, the end of the OFDMA/MU-MIMO datatransmission. Alternatively, the poll frames may appear on differentclusters simultaneously or at different times so that STAs donot need toswitch clusters after reception of the data transmission.

FIG. 30 illustrates a polled ACK sequence when STAs share clusters,e.g., OFDMA & MU-MIMO. The example of FIG. 30 shows an ACK schedulingexample for MU-MIMO/OFDMA receive capability of a MU-MIMO/OFDMA datatransmitter. With the example of FIG. 30, STA1 receives on clusters 1and 2 and is given permission to transmit on cluster 1 and cluster 2 byreceipt of a poll frame on cluster 1. STA2 does not receive any data inthe MU-MIMO/OFDMA transmission. STA3 and STA4 receive on cluster 3 afterreceiving a poll frame on cluster 3, transmit on cluster 3. STA5receives on cluster 4 and after receiving a poll frame on cluster 3,transmits on cluster 4. The polls sent to STAs 3, 4, 5 are transmittedas a single MU-MIMO/OFDMA transmission by STA0.

FIG. 31 illustrates another example of a polled ACK sequence when STAsshare clusters, e.g., OFDMA & MU-MIMO. The example of FIG. 31 shows anACK scheduling example for MU-MIMO/OFDMA receive capability of aMU-MIMO/OFDMA data transmitter. With the example of FIG. 31, STA1receives on clusters 1 and 2 and is given permission to transmit oncluster 1 and cluster 2, STA2 does not receive any data in theMU-MIMO/OFDMA transmission, STA3 and STA4 receive and transmit oncluster 3, and STA5 receives and transmits on cluster 4. Note that theoperations of FIG. 31 differ slightly from those of FIG. 30 with regardto STA1 sends a single ACK or BA frame instead of a pair of ACK or BAframes.

FIG. 32 illustrates another example of a polled ACK sequence when STAsshare clusters, e.g., OFDMA & MU-MIMO. The example of FIG. 32 shows anACK scheduling example for MU-MIMO/OFDMA receive capability of aMU-MIMO/OFDMA data transmitter. With the example of FIG. 31, STA1receives on clusters 1 and 2 and is allowed to transmit only on cluster1, but in doing so, transmits not only an ACK or BA, but also some DATAto STA0 as the extra time required to do so is indicated by the pollframe sent from STA0 to STA1. STA2 does not receive any data in theMU-MIMO/OFDMA transmission. STA3 and STA4 receive and transmit oncluster 3, and STA5 receives and transmits on cluster 4. STA3 and STA4also receive indication in their received poll frames that DATA may besent to STA0.

FIG. 32 illustrates a time slotted or scheduled acknowledgement sequencewith aggregated data. With the example of FIG. 32, STA1 receives data onclusters 1 and 2, receives poll on clusters 1, 2, 3, 4 and transmits ACKon cluster 1 and cluster 2 and also some DATA to STA0 as the extra timerequired to do so is indicated by the poll frame sent from STA0 to STA1,STA2 does not receive any data in the MU-MIMO/OFDMA transmission. STA3and STA4 receive and transmit on cluster 3. STA5 receives and transmitson cluster 4. STA3 and STA4 also receive indication in their receivedpoll frames that DATA may be sent to STA0.

FIGS. 33 and 34 are signal diagrams illustrating various examples ofreverse data aggregations ACK operations of transmitting and receivingWLAN devices. With these examples, the ACK can be aggregated withreverse data which may be OFDMA/MU-MIMO. With these operations thescheduled arrangement reduces collision overhead. Further, the clusterassignment(s) may be different for data transmission and reverse datatransmission. The reverse data transmissions may be based upon reversedata permission according to acknowledgement time slot duration and/oraccording to explicit permission to transmit reverse data, e.g., areverse data permission bit may be included in the SACK field of theMU-MIMO/OFDMA data transmission.

FIG. 33 illustrates a time slotted or scheduled acknowledgement sequencewith aggregated data. With the example of FIG. 33, STA1 receives onclusters 1 and 2 and transmits ACK and DATA on cluster 1 and cluster 2,STA2 does not receive any data in the MU-MIMO/OFDMA transmission, STA3and STA4 receive and transmit on cluster 3, and STA5 receives andtransmits on cluster 4.

FIG. 34 illustrates a time slotted or scheduled acknowledgement sequencewith aggregated data. With the example of FIG. 34, STA1 receives oncluster 1 and transmits ACK and DATA on cluster 2, STA2 does not receiveany data in the MU-MIMO/OFDMA transmission, STA3 and STA4 receive andtransmit on cluster 3, and STA5 receives and transmits on cluster 4.

It is noted that the various modules and/or circuitries (e.g., basebandprocessing modules, encoding modules and/or circuitries, decodingmodules and/or circuitries, etc., etc.) described herein may be a singleprocessing device or a plurality of processing devices. Such aprocessing device may be a microprocessor, micro-controller, digitalsignal processor, microcomputer, central processing unit, fieldprogrammable gate array, programmable logic device, state machine, logiccircuitry, analog circuitry, digital circuitry, and/or any device thatmanipulates signals (analog and/or digital) based on operationalinstructions. The operational instructions may be stored in a memory.The memory may be a single memory device or a plurality of memorydevices. Such a memory device may be a read-only memory (ROM), randomaccess memory (RAM), volatile memory, non-volatile memory, staticmemory, dynamic memory, flash memory, and/or any device that storesdigital information. It is also noted that when the processing moduleimplements one or more of its functions via a state machine, analogcircuitry, digital circuitry, and/or logic circuitry, the memory storingthe corresponding operational instructions is embedded with thecircuitry comprising the state machine, analog circuitry, digitalcircuitry, and/or logic circuitry. In such an embodiment, a memorystores, and a processing module coupled thereto executes, operationalinstructions corresponding to at least some of the steps and/orfunctions illustrated and/or described herein.

It is also noted that any of the connections or couplings between thevarious modules, circuits, functional blocks, components, devices, etc.within any of the various diagrams or as described herein may bedifferently implemented in different embodiments. For example, in oneembodiment, such connections or couplings may be direct connections ordirect couplings there between. In another embodiment, such connectionsor couplings may be indirect connections or indirect couplings therebetween (e.g., with one or more intervening components there between).Of course, certain other embodiments may have some combinations of suchconnections or couplings therein such that some of the connections orcouplings are direct, while others are indirect. Differentimplementations may be employed for effectuating communicative couplingbetween modules, circuits, functional blocks, components, devices, etc.without departing from the scope and spirit of the invention.

As one of average skill in the art will appreciate, the term“substantially” or “approximately”, as may be used herein, provides anindustry-accepted tolerance to its corresponding term. Such anindustry-accepted tolerance ranges from less than one percent to twentypercent and corresponds to, but is not limited to, component values,integrated circuit process variations, temperature variations, rise andfall times, and/or thermal noise. As one of average skill in the artwill further appreciate, the term “operably coupled”, as may be usedherein, includes direct coupling and indirect coupling via anothercomponent, element, circuit, or module where, for indirect coupling, theintervening component, element, circuit, or module does not modify theinformation of a signal but may adjust its current level, voltage level,and/or power level. As one of average skill in the art will alsoappreciate, inferred coupling (i.e., where one element is coupled toanother element by inference) includes direct and indirect couplingbetween two elements in the same manner as “operably coupled”. As one ofaverage skill in the art will further appreciate, the term “comparesfavorably”, as may be used herein, indicates that a comparison betweentwo or more elements, items, signals, etc., provides a desiredrelationship. For example, when the desired relationship is that signal1 has a greater magnitude than signal 2, a favorable comparison may beachieved when the magnitude of signal 1 is greater than that of signal 2or when the magnitude of signal 2 is less than that of signal 1.

Various aspects of the present invention have also been described abovewith the aid of method steps illustrating the performance of specifiedfunctions and relationships thereof. The boundaries and sequence ofthese functional building blocks and method steps have been arbitrarilydefined herein for convenience of description. Alternate boundaries andsequences can be defined so long as the specified functions andrelationships are appropriately performed. Any such alternate boundariesor sequences are thus within the scope and spirit of the claimedinvention.

Various aspects of the present invention have been described above withthe aid of functional building blocks illustrating the performance ofcertain significant functions. The boundaries of these functionalbuilding blocks have been arbitrarily defined for convenience ofdescription. Alternate boundaries could be defined as long as thecertain significant functions are appropriately performed. Similarly,flow diagram blocks may also have been arbitrarily defined herein toillustrate certain significant functionality. To the extent used, theflow diagram block boundaries and sequence could have been definedotherwise and still perform the certain significant functionality. Suchalternate definitions of both functional building blocks and flowdiagram blocks and sequences are thus within the scope and spirit of theclaimed invention.

One of average skill in the art will also recognize that the functionalbuilding blocks, and other illustrative blocks, modules and componentsherein, can be implemented as illustrated or by discrete components,application specific integrated circuits, processors executingappropriate software and the like or any combination thereof.

Moreover, although described in detail for purposes of clarity andunderstanding by way of the aforementioned embodiments, various aspectsof the present invention are not limited to such embodiments. It will beobvious to one of average skill in the art that various changes andmodifications may be practiced within the spirit and scope of theinvention, as limited only by the scope of the appended claims.

Mode Selection Tables:

TABLE 1 2.4 GHz, 20/22 MHz channel BW, 54 Mbps max bit rate Code RateModulation Rate NBPSC NCBPS NDBPS EVM Sensitivity ACR AACR 1 Barker BPSK2 Barker QPSK 5.5 CCK 6 BPSK 0.5 1 48 24 −5 −82 16 32 9 BPSK 0.75 1 4836 −8 −81 15 31 11 CCK 12 QPSK 0.5 2 96 48 −10 −79 13 29 18 QPSK 0.75 296 72 −13 −77 11 27 24 16-QAM 0.5 4 192 96 −16 −74 8 24 36 16-QAM 0.75 4192 144 −19 −70 4 20 48 64-QAM 0.666 6 288 192 −22 −66 0 16 54 64-QAM0.75 6 288 216 −25 −65 −1 15

TABLE 2 Channelization for Table 1 Channel Frequency (MHz) 1 2412 2 24173 2422 4 2427 5 2432 6 2437 7 2442 8 2447 9 2452 10 2457 11 2462 12 2467

TABLE 3 Power Spectral Density (PSD) Mask for Table 1 PSD Mask 1Frequency Offset dBr −9 MHz to 9 MHz 0 +/−11 MHz −20 +/−20 MHz −28 +/−30MHz and greater −50

TABLE 4 5 GHz, 20 MHz channel BW, 54 Mbps max bit rate Code RateModulation Rate NBPSC NCBPS NDBPS EVM Sensitivity ACR AACR 6 BPSK 0.5 148 24 −5 −82 16 32 9 BPSK 0.75 1 48 36 −8 −81 15 31 12 QPSK 0.5 2 96 48−10 −79 13 29 18 QPSK 0.75 2 96 72 −13 −77 11 27 24 16-QAM 0.5 4 192 96−16 −74 8 24 36 16-QAM 0.75 4 192 144 −19 −70 4 20 48 64-QAM 0.666 6 288192 −22 −66 0 16 54 64-QAM 0.75 6 288 216 −25 −65 −1 15

TABLE 5 Channelization for Table 4 Frequency Frequency Channel (MHz)Country Channel (MHz) Country 240 4920 Japan 244 4940 Japan 248 4960Japan 252 4980 Japan 8 5040 Japan 12 5060 Japan 16 5080 Japan 36 5180USA/Europe 34 5170 Japan 40 5200 USA/Europe 38 5190 Japan 44 5220USA/Europe 42 5210 Japan 48 5240 USA/Europe 46 5230 Japan 52 5260USA/Europe 56 5280 USA/Europe 60 5300 USA/Europe 64 5320 USA/Europe 1005500 USA/Europe 104 5520 USA/Europe 108 5540 USA/Europe 112 5560USA/Europe 116 5580 USA/Europe 120 5600 USA/Europe 124 5620 USA/Europe128 5640 USA/Europe 132 5660 USA/Europe 136 5680 USA/Europe 140 5700USA/Europe 149 5745 USA 153 5765 USA 157 5785 USA 161 5805 USA 165 5825USA

TABLE 6 2.4 GHz, 20 MHz channel BW, 192 Mbps max bit rate TX ST Anten-Code Code Rate nas Rate Modulation Rate NBPSC NCBPS NDBPS 12 2 1 BPSK0.5 1 48 24 24 2 1 QPSK 0.5 2 96 48 48 2 1 16-QAM 0.5 4 192 96 96 2 164-QAM 0.666 6 288 192 108 2 1 64-QAM 0.75 6 288 216 18 3 1 BPSK 0.5 148 24 36 3 1 QPSK 0.5 2 96 48 72 3 1 16-QAM 0.5 4 192 96 144 3 1 64-QAM0.666 6 288 192 162 3 1 64-QAM 0.75 6 288 216 24 4 1 BPSK 0.5 1 48 24 484 1 QPSK 0.5 2 96 48 96 4 1 16-QAM 0.5 4 192 96 192 4 1 64-QAM 0.666 6288 192 216 4 1 64-QAM 0.75 6 288 216

TABLE 7 Channelization for Table 6 Channel Frequency (MHz) 1 2412 2 24173 2422 4 2427 5 2432 6 2437 7 2442 8 2447 9 2452 10 2457 11 2462 12 2467

TABLE 8 5 GHz, 20 MHz channel BW, 192 Mbps max bit rate TX ST Anten-Code Code Rate nas Rate Modulation Rate NBPSC NCBPS NDBPS 12 2 1 BPSK0.5 1 48 24 24 2 1 QPSK 0.5 2 96 48 48 2 1 16-QAM 0.5 4 192 96 96 2 164-QAM 0.666 6 288 192 108 2 1 64-QAM 0.75 6 288 216 18 3 1 BPSK 0.5 148 24 36 3 1 QPSK 0.5 2 96 48 72 3 1 16-QAM 0.5 4 192 96 144 3 1 64-QAM0.666 6 288 192 162 3 1 64-QAM 0.75 6 288 216 24 4 1 BPSK 0.5 1 48 24 484 1 QPSK 0.5 2 96 48 96 4 1 16-QAM 0.5 4 192 96 192 4 1 64-QAM 0.666 6288 192 216 4 1 64-QAM 0.75 6 288 216

TABLE 9 channelization for Table 8 Frequency Frequency Channel (MHz)Country Channel (MHz) Country 240 4920 Japan 244 4940 Japan 248 4960Japan 252 4980 Japan 8 5040 Japan 12 5060 Japan 16 5080 Japan 36 5180USA/Europe 34 5170 Japan 40 5200 USA/Europe 38 5190 Japan 44 5220USA/Europe 42 5210 Japan 48 5240 USA/Europe 46 5230 Japan 52 5260USA/Europe 56 5280 USA/Europe 60 5300 USA/Europe 64 5320 USA/Europe 1005500 USA/Europe 104 5520 USA/Europe 108 5540 USA/Europe 112 5560USA/Europe 116 5580 USA/Europe 120 5600 USA/Europe 124 5620 USA/Europe128 5640 USA/Europe 132 5660 USA/Europe 136 5680 USA/Europe 140 5700USA/Europe 149 5745 USA 153 5765 USA 157 5785 USA 161 5805 USA 165 5825USA

TABLE 10 5 GHz, with 40 MHz channels and max bit rate of 486 Mbps TX STAnten- Code Code Rate nas Rate Modulation Rate NBPSC 13.5 Mbps 1 1 BPSK0.5 1 27 Mbps 1 1 QPSK 0.5 2 54 Mbps 1 1 16-QAM 0.5 4 108 Mbps 1 164-QAM 0.666 6 121.5 Mbps 1 1 64-QAM 0.75 6 27 Mbps 2 1 BPSK 0.5 1 54Mbps 2 1 QPSK 0.5 2 108 Mbps 2 1 16-QAM 0.5 4 216 Mbps 2 1 64-QAM 0.6666 243 Mbps 2 1 64-QAM 0.75 6 40.5 Mbps 3 1 BPSK 0.5 1 81 Mbps 3 1 QPSK0.5 2 162 Mbps 3 1 16-QAM 0.5 4 324 Mbps 3 1 64-QAM 0.666 6 365.5 Mbps 31 64-QAM 0.75 6 54 Mbps 4 1 BPSK 0.5 1 108 Mbps 4 1 QPSK 0.5 2 216 Mbps4 1 16-QAM 0.5 4 432 Mbps 4 1 64-QAM 0.666 6 486 Mbps 4 1 64-QAM 0.75 6

TABLE 11 Power Spectral Density (PSD) mask for Table 10 PSD Mask 2Frequency Offset dBr −19 MHz to 19 MHz 0 +/−21 MHz −20 +/−30 MHz −28+/−40 MHz and greater −50

TABLE 12 Channelization for Table 10 Frequency Frequency Channel (MHz)Country Channel (MHz) County 242 4930 Japan 250 4970 Japan 12 5060 Japan38 5190 USA/Europe 36 5180 Japan 46 5230 USA/Europe 44 5520 Japan 545270 USA/Europe 62 5310 USA/Europe 102 5510 USA/Europe 110 5550USA/Europe 118 5590 USA/Europe 126 5630 USA/Europe 134 5670 USA/Europe151 5755 USA 159 5795 USA

1. An apparatus, comprising: an encoder for encoding at least oneinformation bit thereby generating a plurality of coded bits; a clusterparser for assigning the plurality of coded bits among a plurality ofclusters corresponding to a plurality of wireless communication devices;and a plurality of antennae for transmitting the plurality of codedbits, using the plurality of clusters, to the plurality of wirelesscommunication devices.
 2. The apparatus of claim 1, wherein: a firstsubset of the plurality of coded bits being assigned among a first ofthe plurality of clusters; a second subset of the plurality of codedbits being assigned among a second of the plurality of clusters; a firstsubset of the plurality of antennae transmitting the first subset of theplurality of coded bits, using the first of the plurality of clusters,to a first of the plurality of wireless communication devices; and asecond subset of the plurality of antennae transmitting the secondsubset of the plurality of coded bits, using the second of the pluralityof clusters, to a second of the plurality of wireless communicationdevices.
 3. The apparatus of claim 2, wherein: the first subset of theplurality of antennae and the second subset of the plurality of antennaeincluding at least one common antenna.
 4. The apparatus of claim 1,wherein: a first subset of the plurality of coded bits being assignedamong a first of the plurality of clusters; and a second subset of theplurality of coded bits being assigned among a second of the pluralityof clusters; and further comprising: a plurality of stream parsers for:allocating the first subset of the plurality of coded bits to a firstspatial stream; and allocating the second subset of the plurality ofcoded bits to a second spatial stream.
 5. The apparatus of claim 4,wherein: a first subset of the plurality of antennae transmitting thefirst spatial stream; and a second subset of the plurality of antennaetransmitting the second spatial stream.
 6. The apparatus of claim 1,wherein: a first subset of the plurality of coded bits including a firstnumber of coded bits; and a second subset of the plurality of coded bitsincluding a second number of coded bits.
 7. The apparatus of claim 1,wherein: one of the plurality of clusters being composed of at least onechannel within at least one band.
 8. The apparatus of claim 1, wherein:a first of the plurality of clusters being composed of at least onechannel within a first band; and a second of the plurality of clustersbeing composed of at least one channel within a second band.
 9. Theapparatus of claim 1, wherein: a first of the plurality of clustersbeing composed of a first plurality of channels among a first band and asecond band; and a second of the plurality of clusters being composed ofa second plurality of channels among a third band and a fourth band. 10.The apparatus of claim 9, wherein: the third band being the first band;and the fourth band being the second band.
 11. The apparatus of claim 1,further comprising: a plurality of encoders for encoding a plurality ofinformation bits thereby generating the plurality of coded bits; andwherein: a first of the plurality of encoders corresponding to a firstof the plurality of wireless communication devices; and a second of theplurality of encoders corresponding to a second of the plurality ofwireless communication devices.
 12. The apparatus of claim 11, wherein:the first of the plurality of encoders employing a first errorcorrection code (ECC); and the second of the plurality of encodersemploying a second ECC.
 13. The apparatus of claim 1, wherein: theapparatus being an access point (AP); and the plurality of wirelesscommunication devices being a plurality of wireless stations (STAs). 14.An apparatus, comprising: a plurality of encoders for encoding aplurality of information bits thereby generating a plurality of codedbits; a cluster parser for: assigning a first subset of the plurality ofcoded bits among a first cluster; and assigning a second subset of theplurality of coded bits among a second cluster; a plurality of streamparsers for: allocating the first subset of the plurality of coded bitsamong the first cluster to a first spatial stream; and allocating thesecond subset of the plurality of coded bits among the first cluster tothe second spatial stream; and a plurality of antennae for: inaccordance with the first spatial stream, transmitting to a first of aplurality of wireless communication devices; and in accordance with thesecond spatial stream, transmitting to a second of the plurality ofwireless communication devices.
 15. The apparatus of claim 14, wherein:a first subset of the plurality of antennae transmitting the firstspatial stream; and a second subset of the plurality of antennaetransmitting the second spatial stream.
 16. The apparatus of claim 15,wherein: the first subset of the plurality of antennae and the secondsubset of the plurality of antennae including at least one commonantenna.
 17. The apparatus of claim 14, wherein: the first subset of theplurality of coded bits including a first number of coded bits; and thesecond subset of the plurality of coded bits including a second numberof coded bits.
 18. The apparatus of claim 14, wherein: the first clusterbeing composed of at least one channel within a first band; and thesecond cluster being composed of at least one channel within a secondband.
 19. The apparatus of claim 14, wherein: the first cluster beingcomposed of a first plurality of channels among a first band and asecond band; and the second cluster being composed of a second pluralityof channels among a third band and a fourth band.
 20. The apparatus ofclaim 19, wherein: the third band being the first band; and the fourthband being the second band.
 21. The apparatus of claim 14, wherein: afirst of the plurality of encoders employing a first error correctioncode (ECC); and a second of the plurality of encoders employing a secondECC.
 22. The apparatus of claim 14, wherein: the apparatus being anaccess point (AP); and the plurality of wireless communication devicesbeing a plurality of wireless stations (STAs).
 23. A method foroperating a communication device, the method comprising: operating anencoder for encoding at least one information bit thereby generating aplurality of coded bits; assigning the plurality of coded bits among aplurality of clusters corresponding to a plurality of wirelesscommunication devices; and operating a plurality of antennae fortransmitting the plurality of coded bits, using the plurality ofclusters, to the plurality of wireless communication devices.
 24. Themethod of claim 23, further comprising: assigning a first subset of theplurality of coded bits among a first of the plurality of clusters;assigning a second subset of the plurality of coded bits among a secondof the plurality of clusters; operating a first subset of the pluralityof antennae for transmitting the first subset of the plurality of codedbits, using the first of the plurality of clusters, to a first of theplurality of wireless communication devices; and operating a secondsubset of the plurality of antennae for transmitting the second subsetof the plurality of coded bits, using the second of the plurality ofclusters, to a second of the plurality of wireless communicationdevices.
 25. The method of claim 24, wherein: the first subset of theplurality of antennae and the second subset of the plurality of antennaeincluding at least one common antenna.
 26. The method of claim 23,further comprising: assigning a first subset of the plurality of codedbits among a first of the plurality of clusters; and assigning a secondsubset of the plurality of coded bits among a second of the plurality ofclusters; allocating the first subset of the plurality of coded bits toa first spatial stream; and allocating the second subset of theplurality of coded bits to a second spatial stream.
 27. The method ofclaim 26, further comprising: transmitting the first spatial streamusing a first subset of the plurality of antennae; and transmitting thesecond spatial stream using a second subset of the plurality ofantennae.
 28. The method of claim 23, wherein: a first subset of theplurality of coded bits including a first number of coded bits; and asecond subset of the plurality of coded bits including a second numberof coded bits.
 29. The method of claim 23, wherein: one of the pluralityof clusters being composed of at least one channel within at least oneband.
 30. The method of claim 23, wherein: a first of the plurality ofclusters being composed of at least one channel within a first band; anda second of the plurality of clusters being composed of at least onechannel within a second band.
 31. The method of claim 23, wherein: afirst of the plurality of clusters being composed of a first pluralityof channels among a first band and a second band; and a second of theplurality of clusters being composed of a second plurality of channelsamong a third band and a fourth band.
 32. The method of claim 31,wherein: the third band being the first band; and the fourth band beingthe second band.
 33. The method of claim 23, further comprising:operating a plurality of encoders for encoding a plurality ofinformation bits thereby generating the plurality of coded bits; andwherein: a first of the plurality of encoders corresponding to a firstof the plurality of wireless communication devices; and a second of theplurality of encoders corresponding to a second of the plurality ofwireless communication devices.
 34. The method of claim 33, furthercomprising: operating the first of the plurality of encoders using afirst error correction code (ECC); and operating the second of theplurality of encoders using a second ECC.
 35. The method of claim 23,wherein: the communication device being an access point (AP); and theplurality of wireless communication devices being a plurality ofwireless stations (STAs).